Montblanc MB M13.21 Manual Del Usuario página 9

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Calibre MB M13.21 Calibre MB M13.21
Chronographe Monopoussoir
Available in the Heritage Spirit collection and 1858
It was during the 20 th century that the Villeret Manufacture, known at the time by the name of Minerva,
produced the first wristwatches equipped with a mechanical chronograph. These watches were real
instruments that united a high level of functionality with outstanding mastery of the watchmaker's art. Fully
produced, decorated and assembled by hand, the calibre MB M13.21 has the distinguishing feature of being
controlled by a single push-piece built into the crown. The chronograph function is displayed through the
central chronograph hand and the 30-minute counter at 3 o'clock.
Under its screwed sapphire-crystal back, the calibre reveals its watch-plate and bridges in German silver and
its steel parts hand-chamfered by the master watchmakers of the Montblanc Manufacture in Villeret.
The calibre MB M13.21 comprises a classical gear train with horizontal clutch-wheel, a column-wheel to
control the chronograph functions and a large screwed balance-wheel, 14.5 mm in diameter, with a high
moment of inertia of 59 mg.cm², oscillating at a frequency of
18,000 vibrations per hour (2.5 Hz).
Its power reserve is about 50-55 hours and ensures remarkable wearing comfort.